I'm part way through rigging a skirt for V4 that I created in blender and have encountered an issue that is baffling me on the setting up of joints, so I'm wondering if those of you out there with experience in this area might have any pointers.

The skirt uses additional bones that are parented to the hip for a series of separate panels and the majority of these seem to work fine. However, some do not - despite being outside the green inner mat sphere (using spherical zones) as you can see in the picture there is a line of vertices that are being randomly affected it seems when the joint is moved. The only way to stop this happening is to move the inner sphere upwards so that it covers the majority of the panel only this gives a very stiff and wooden effect which I'm not after at all - I want something with more give like material, which works on the other panels when the inner sphere is moved towards the end of the panel.

Any ideas anyone?